Roe 8 is a 5km extension from Kwinana Freeway to Stock Road via Beeliar Wetlands and the first stage of the PFL.

The State Government was believed to be close to signing off contracts with a consortium to begin work on Roe 8 early in 2016.

But, after a crowd-sourced legal bid to review the decision, Chief Justice Wayne Martin placed a roadblock in front of the controversial project.

He said “the EPA took no account of its own published policies at the time it made its decision and provided its report to the Minister” and “the environmental impact assessment undertaken by the EPA was invalid”.

Mr Barnett said he was disappointed with the decision but the State Government was likely to re-load and go again.

“We’ve yet to have time to really study the full implications of (the decision) but my best guess at this stage is that it will mean the State Government will need to re-do all or part of the environmental approvals for Roe 8,” he said.

“If we have to re-do it that’s what we will do and the project will proceed.”

Rethink the Link co-convener Kate Kelly described the court decision as a victory for the community and for justice.

“We know there could be more challenges to come but for now we know our wetlands are safe,” she said.

“Our support will remain steadfast and resolute. We know that no matter what now, we have the community behind us.”

She said the PFL should be scrapped in favour of “the logical alternative” – an outer harbour.

Cockburn Mayor Logan Howlett said the crowd-funded campaign to challenge the approvals process has reached an incredible result.

“We call upon the State Government to take note of this decision to the Rethink the Perth Freight Link and move to developing the Outer Harbour as a priority,” he said.

Perth MHR Alannah MacTiernan called for the Federal Government to ditch its $925m worth of funding for the project in favour of ready-to-go rail projects. But Melville Mayor Russell Aubrey said he was disappointed by the decision, labelling the outer harbour option a “disaster for the State”.

“Main Roads and the Department of Transport have been saying the same things for 15 years – Roe 8 has to be built,” he said.

“The State Government has been voted in twice now on the platform of building Roe 8 and this latest ruling is just delaying an inevitable project.”